Electric-lighting device.



E. ESSICH. ELECTRIC LIGHTING nEvIcE. APPLICATION FILED APII.22. '19T-5.

Patented Feb. 15,1916.

ITE S EUGEN ESSICH, 0F STUTTGART, GERMANY.

ELECTRIC-LIGHTING DEVICE.

Specification of Letters Patent.

Patented Feb. 15, 19,16.

Application filed April 22, 1.915. Serial No. 23,199.

I To ZZ v20710111 yit may Conf-ern Be it known that I. EITGEN EssICH, of T7 Hohenheimerstrasse, Stuttgart, in the Kingdom of IVurttemberg, German Empire, civil engineer, have invented certain new and useful Improvements in lElectric-Lighting Devices, of which the following is a specilication.

My invention relates to electric glow lamps and its particular object is to reduce the radiation of heat in such lamps in order to increase their lighting capacity.

The electric energy supplied to a glow lamp is transformed therein into heatand light; the smaller the quota of heat radiated into the surrounding atmosphere,the greater the lighting power of the lamp. The modern metal filament glow lamps having the bulb filled with an inert gas have la comparatively short life; when the filament is consumed the whole lamp including the fittings is almost worthless. Moreover in these lamps a heat emission takes place which is favored by the circulation of the gas filling the bulb. It may not be impossible to diminish the heat emission by providing such glow lamps with a double walled bulb, the space between the Vouter and inner walls of the bulb being exhausted. Such a construction however is far more expensive than the ordinary wire lamps and owing to the short life of such lamps it is not commercial. Besides one must take into account that in lamps filled with gas the emission of heat through the metal cap is rather high. Therefore, in order to keep the losses of heatdown, it is necessary to proceed quite differently.

The device according to the present invention has an interchangeable lamp filled with an inert gas. this lamp' constituting the lamp proper and being provided with the metal wire or other filament and a small metal cap of special construction. This lamp or burner is inserted in and almost entirely surrounded by a separate doublewalled glass bulb or Dewar vessel exhausted between the outer and inner walls in such a fashion as to render the losses of heat, especially the heat emission through the cap and ttings, as insignificant as possible.

Figures l, 2 and 3 of the drawings afiixed t-o this specification show some forms of an improved glow lamp according to-my invention. allthe modifications being represented in longitudinal section.

Fig. l shows the plug g of Fig. 1 in cross section and illustrates the means for securing electrical connection between the terminal Yplugs z', h of the same.

Fig. 5 shows the plug g of Figs. Q and 3 in cross section and illustrates the means for securing electrical connection through the same.

Fig. 6 illustrates the slotted perforations in the sleeve c.

In the lamp shown in Figure 1 a, b is the double-walled protecting envelop. A slender lamp (Z is inserted in the hollow of the double-walled bulb a, b; the filament is not shown for the sake of clearness. A metal sleeve c is cemented into and thus becomes aportion of the neck of the double-walled bulb a., b, the inner part of said sleeve being slotted in order to keep its heat-conductivity as low as possible. The outer part is provided with screw threads both internally and externally. The lamp cl is provided at its base with a terminal ring c and a terminal block 7'. A separate screw-threaded heat-insulating plug g is screwed into t-he sleeve 0, said plug being provided with terminal blocks z' and h. If the plug is screwed down into the sleeve c, block 'L' coming in contact with block f of the lamp presses ring f against the inner ange ofthe sleeve. lVhen the whole device is screwed into a lamp holder the current will iiow through sleeve c, ring e, the lamp filament and blocks f, z' and z. The distance 7c between the contact face of terminal 7' of the lamp and the end of the. double-walled bulb being rather long and there being no broad metal surfaces provided in this lamp which might favor the transmission of heat to the out-A side, the transmission of heat to the cap is very low indeed.

In the modifications shown in Figs. 2 and 3 the'heat-insulating plug g is screwed into the neck of the protective envelop a b', either a screw threaded metal sleeve Z being cemented into the neck, orv the glass walls m of the neck being themselves screwthreaded. rIhe lamp d is provided with a screw-threaded metal cap a designed to be screwed into a corresponding metal sleeve a. of the plug, said plug being provided with a terminal block g at one end, and

with a screw threaded capo and terminal` block p to be inserted in the lamp holder,

incombination an incandescent lamp containing a body of gas, and vacuum insulation means including a hollow lamp carrying member, for minimizing the escape of heat transversely and axially at both ends of said lamp.

3. In an electric lighting device, the combination with a gas filled incandescent lamp,

and a socket in which the same is mounted;

of a heat insulating pocket-like double- Walled vacuum envelop adapted lto inclose both lamp and socket and readily detachable therefrom, said envelop including a heat insulating plug adapted to close the aperture of introduction of said envelop.

4. In an electric lighting device, in combination a gas-lled incandescent lamp having a socket, a pocket-like double walled exhausted envelop inclosing said lamp and socket, and a heat insulating plug, extending transversely across the lamp axis and the aperture of introduction of` said envelop, and adapted to effect heat insulation axially of said lamp.

5. In an electric lighting device, the combination with a gas iilled incandescent lamp, and a socket in which the same is mounted;

Aof a heat insulating pocket-like doublewalled vacuum envelop adapted to inclose both lamp and socket and readily detachable therefrom, and a heat insulating plug associated with said socket and adapted to effect electrical connection'with the lamp.

6. In an. electric lighting device, in combination, a gas filled incandescent lamp, a double-walled protective glass envelop exhausted between its outer and inner walls surrounding said lamp and a plug adapted to close the aperture of introduction of said envelop and to effect an electrical connection between said lamp and a lamp holder, said plug being hollow and exhausted.

7. In an electric lighting device, in combination, a gas filled incandescent lamp, a double-walled protective glass envelop exhausted between its outer and inner walls surrounding said lamp, a heat insulating plug removably arranged in the neck of said envelop, a screw-threaded sleeve associated with said plug, a screw cap on said lamp adapted to be screwed into the plug sleeve and means for securing electrical connection between the sleeve and a lamp holder. y

8. In an electric lighting device, in combination, a gas filled incandescent lamp, a double-walled protective glass envelop exhausted between its outer and inner walls surrounding said lamp, `a heat insulating plug removably arranged in the neck of said envelop, a screw threaded sleeve associated with said plug, and a terminal on said lamp adapted to make an electrical connection with said sleeve. l

In testimony whereof, I aiix my signature, in the presence of two witnesses.

EUGEN ESSICH. Witnesses:

ANTON ARETZ, ERNEST ENTLEMANN. 

